Norman mccullocii



duced to nitric oxide, (NO.)

UNITED STATES NORMAN MCOULLOGH, OF GLASGOW, SCOTLAND.

METHOD OF OXlDlZlNG PROTOSALTS OF IRON TO PERSALTS.

SPECIFICATION forming part of Letters Patent No. 548,580, dated October 22, 1895, Application filed July 24,1895. Serial No. 657,034. (N specimens-l To aZZ whom it may concern.-

Be it known that I, NORMAN MCCULLOCH, chemist, a subject of the Queen of the United Kingdom of Great Britain and Ireland, residing at No. 7 Melrose Street, Glasgow, in the county of Lanark, Scotland, have invented a Method of Oxidizing the Protosalts of Iron to the Persalts, of which the following is a specification.

This invention relates to a method for effecting the combination of protoxide of iron in acid solution with free oxygen, such as atmospheric oxygen, with consequent formation of a. persalt of iron, (which may be basic or normal, according to the proportion of acid in, the original solution,) by agitating the ferrous solution with a sufficient volume of air in presence of a suitable proportion of either nitric oxide (NO) or nitrogen peroxide, (NO The function of these nitrogen oxides is to act as carriers of oxygen from the air to the ferrous solution or as catalytic agents. This they effect through the Well-known property of nitric oxide (NO) to combine directly with free oxygen to form nitrogen peroxide, (N0 which is a powerful oxidizing body. The nitrogen peroxide (N0 in presence of an iron protosalt instantly parts with one-half of its combined oxygen to the iron and is re- This inherent power of regeneration theoretically enables the nitrogen oxides specified to bring about the chemical combination of an infinitely large proportion of oxygen and protosalt of iron, and in practice it is observed that the catalytic action of the aforementioned nitrogen oxides ceases only with the conversion of those compounds to substances not possessed of this power to act as oxygen carriers under the conditions; but the loss of active nitrogen oxides from this and other causes is small relative to the proportion of atmospheric oxygen it can render practically available as an oxidant, it having been found that one volume of nitric oxide can influence the rapid chemical combination of at least fourteen volumes of oxygen under the conditions described herein.

'Io practically apply the foregoing principle of oxidizing ferrous salts with air many forms of apparatus naturally suggest them selves; but excellent results have been ob tained. by using as the oxidizing plant a very simple apparatus of which the following is a general but sufficiently particular description. It may consist of a cylindrical Wooden vessel about six feet indiameter and six feet long and closed at both ends with wooden lids. These lids are each fitted with bearings for the axle of a wooden agitator which revolves in the interior of the vessel. This agitator is fitted with wooden vanes, so that by its revolving action it not only effects a thorough commingling of the liquid and gaseous contents of the vessel, but a rapid replacement of the latter with external air when the air-holes, with which the ends and cylindrical side of the apparatus are pierced, are opened. Into this apparatus is conveyed an amount of ferrous solution commensurate with the air capacity of the plant to contain suftioientoxygen to oxidize the iron and an amount of nitric oxide or its equivalent in nitrogen peroxide, in the proportion of about two and one-third parts per one hundred parts of iron to be oxidized. The agitator is then set to work until the dark chocolate color of the solution changes to reddish yellow, which is a convenient indication that the oxidation of the iron is complete. The liquid contents of the chamber are then run off to make way for another portion of ferrous solution and the air and nitric oxide are renewed from time to time, as required.

Details not touched upon in describing the above apparatus and the method of its manipulation will be readily understood.

1 may mention here that as most persalts of iron have a strongly-corrosive action on the metals generally, we are limited, practically, to the use of wood or silicious material in constructing those parts of the above apparatus which come into contact with the iron salts and nitric oxides.

I claim- The method of oxidizing ferrous solutions by agitating the iron solution with air in amount at least equivalent to effect the complete oxidation of the iron, and in presence of nitric oxide or nitrogen peroxide, in the proportion of about two and one third parts nitric oxide or nitrogen peroxide per one hundred parts of iron to be oxidized, as described.

7 NORMAN MoOULLOOH. Witnesses:

JAMES CHALK, .Aaonrexno MoaEIsoN. 

